The latest offering from Mares is the MR12 Akros regulator: virtually the same thing as Voltrex, but with a lightweight plastic second stage. John Bantin took it down for testing
Mares is an Italian company which has progressed in leaps and bounds in its R&D in recent years. The MR12 Akros regulator, its latest breathing valve, is virtually a Mares Voltrex but with a lightweight, all-plastic second stage as an alternative to the heavier metal second stage of the Voltrex or Abyss.
To improve the coldwater performance of a plastic second stage the Akros has unique metal foil inserts set within its body. These act as heat exchangers, picking up heat from the water and warming the air which had been cooled as it was subjected to a drop in pressure at the first stage.
High-performance regulators deliver air so cleanly that a drop in pressure directly behind the pressure-sensitive diaphragm of the second stage is often caused. This pulls the diaphragm inward, rather like pressing the purge button, and increases the airflow further. This compounded effect results in the familiar freeflow and most manufacturers choose to design in a venturi lever to disrupt the airflow and temporarily redirect some of it onto the inner side of the diaphragm.
Mares does it differently. As with its other regulators, the Akros second stage has a vortex-assisted design in the form of a bypass tube, which allows some air to go directly from the medium-pressure hose to the mouthpiece. This avoids some of the suction effect on the second-stage diaphragm.
The air here meets a pivoting flow-vane, giving a servo action to the user's inhalation. Less effort is needed to draw in air, some of which can be redirected to reduce the chances of freeflow. The pivoting flow-vane closes on exhalation, ensuring that there is no counter-resistance.
The Akros uses the same MR12 first stage as the Voltrex, which is a diaphragm design. It has one high- pressure port, four ordinary MP ports and an oversized MP port which takes the widebore Mares "Dynamic Flow Control"-type hose to the second stage. The idea behind DFC is to allow the air to bypass as much of the intricate mechanism of the valve as can be allowed, keeping its route between cylinder and diver as free as possible of any twists and turns. The widebore hose is part of this strategy.
The ports are arranged radially around the valve first stage, which means that some auxiliary hoses are routed in a rather ungainly manner.
Using this regulator at quite substantial depths, but admittedly in warmish water, I found it was always an extremely easy breathe.
A criticism of the early Abyss regulator, which became apparent only after I had used it extensively, was its tendency to allow water in to the second stage. This happened only under certain circumstances, such as when turning one's head sideways on to a fast current, with the resulting flow of water through the exhaust deflector tee lifting the exhaust valve. It was not a big problem but it alarmed some early purchasers.
The exhaust-port deflector of the Akros (and now both the Voltrex and Abyss) contains a baffle which stops this happening.
You know the scene. The new diver sees his first fish and, overcome with excitement, bangs on his tank with his knife to tell his buddy or instructor.
The Scuba Rattle is another underwater attention-grabbing device: a 6in-long stainless steel tube, enclosed at both ends, filled with a couple of ball bearings or the like and fitted with a short lanyard.
"Scuba Rattle is very easy to use by holding it between thumb and fingers. Now move your hand quickly back and forth," suggested the instructions.
I took it diving but, too embarrassed to use it in the prescribed way, resorted to banging the metal tube against my tank. The result was very much like doing the same thing with a knife. The Scuba Rattle just makes it easier to disturb the peace
The Technisub Look MIG mask has nothing to do with Russian fighter- pilots. MIG stands for "Mist Inhibiting Glass" and this is another new mask from Italy, this time with a coating on the inside of its lenses to stop it steaming up.
I have always done the job with a pea-sized nodule of toothpaste rubbed around the inside of the glass of a new mask to remove the effects of silicone vapour during the manufacturing process, followed by a rinse clean and a liberal coating of spit just before entering the water. Others prefer proprietary demisting agents.
Jumping directly into the hot water of a private swimming pool on a freezing spring day, wearing the Look MIG mask as supplied, proved that the coating worked. As to its longevity, only time will tell!
To reduce the chance of inadvertent damage to the coating, the frame boldly displays the legend "Mist Inhibiting Glass". The example supplied to me came with a crystal-clear silicone skirt and conventional strap buckles which were easy to adjust.
Also available from supplier Aqua-Lung UK are Magica slipper-style fins. They are not so suitable for use with boots but perfect for snorkellers or pool training. They come in colours co-ordinated with masks in the Technisub range - silver, navy blue or lime, with a foot section in black rubber compound - and six sizes from 34/35 to 44/45. It's a pity I take 46/47.
Magica fins cost £17-20, the Look MIG mask £43.
An extra supply of air on the side has always seemed a good idea and it is one which is currently borne out by the common use of twinsets and pony-bottles. Spare Air is an American response to this requirement, but when it was launched in this country my predecessor was not impressed. The importers asked me to give it a second go.
Spare Air is a small cylinder equipped with a fixed breathing valve. It is filled with air by the user and carried in a holster on the weightbelt during the dive to be applied autonomously if needed. It is often carried by leisure divers on the other side of the Atlantic.
Is it of any practical value? In the proper tradition of all Diver's equipment testing, I took it on a series of dives to find out.
At the end of a dive, at around 18m, I exchanged my regulator valve for that of the Spare Air. I immediately discovered that it needed quite a draw to get it to give me the precious air I needed.
In this moment of discovery my buddy was drawn away on a bit of a current, and in the rather poor visibility I was forced to fin after him, sucking heavily. The Spare Air supply was finished before I had made the surface, and I had to revert to my regular supply. Had I made a direct ascent I would have just about made it, but then life isn't like that.
From 30m things were much more serious. I counted six good breaths on the way up, which left me not even in sight of safety. In a real emergency situation I could have been six breaths from death.
Spare Air has a volume of only 200ml. Filled to 200 bar pressure, this gives a total volume of only 40l of "free" air. In contrast an average 12l tank contains 600l of "free" air when down to 50 bar. I can pull in up to 24l on one inhalation at 30m: Spare Air just does not contain enough.
Some of you will suggest special circumstances in which Spare Air would be useful, such as a burst high-pressure hose resulting in a lost air supply. In my experience this happens only when the cylinder is filled to high pressure at the beginning of a dive, and although the effect can be dramatic it still leaves enough air available at the regulator mouthpiece for a safe ascent from almost any depth.
I am sorry to report that carrying Spare Air is likely only to lull the user into a false sense of security, and if you decant air from your diving cylinder (with the adaptor provided) all you are doing is stashing it away in a less accessible place. I recommend instead that you watch your pressure gauge or, better still, get an air-integrated computer.
Spare Air costs £151 (silver) or £161 (blue, black, neon yellow or neon pink).
Now that GPS has made surface navigation so easy, it is a pity that divers still lose their way underwater. If only satellite signals could be used! Still, for those who might have problems using an ordinary compass, Swiss diving computer company Uwatec has come up with an electronic version. Its True Track is a programmable underwater compass.
Don't expect this to answer all the non-thinking diver's navigational problems at a stroke. When I first jumped into the water with it, not fully understanding the instructions, I couldn't make head or tail of what it was trying to tell me. It was something of a relief when it went back into "sleep" mode, and I could resort to the good old low-tech of my traditional swinging magnet.
The True Track is controlled by water-responsive contacts and three tap switches positioned at left, right and top of its LCD display. Using these in combination allows you to set a series of bearings, including reciprocals, and plan your dive route in the most comprehensive way. The instruction manual is dauntingly big, but when all else failed I set out to read it.
After studying it during a 10-hour flight, I have to confess to being none the wiser. Was I thick or what? Befuddled by endless options, it turned out that I had missed out how to turn it on, sight up the lubber-line marks and read the compass bearing directly through the lower window.
The next stage in my learning process was to decide whether to go for magnetic or geographical bearings. Only then did I progress to storing up to nine courses for one dive, together with their reciprocals.
If these devices become popular they will stimulate demand for very detailed dive briefings, along the lines of: progress at 125° until you reach the mushroom-shaped rock, then take a course of 190° to the stern of the wreck, follow the line of the wreck at 220°, and then take a 65° to the big anemone. If you get to the big anemone or down to 125 bars, go back on the reciprocals.
Presetting all this in the dry before you go can avoid mistakes under water. The device costs £130.
The Shark Skin Lycra suit ) is slippery enough to allow another suit to be worn over it easily, should you encounter unexpectedly cold water. It is made of a heavier material than the usual Lycra diveskin, with a thick spinepad running up the back. It also looks much more durable than many Far Eastern products, which can quickly unravel at the seams. It seems about equivalent in insulation value to 2 or 3mm of neoprene. Pack one in your dive bag. It costs £88, takes up little room, and who knows when you'll need the extra warmth? Then again, you might be lucky enough to be going where it's all you need.
The perfect microclimate next to the skin is something few of you probably enjoy inside your drysuits, but it is the promise of Cool fix International, which makes lightweight thermal bodywear.
You don't always want to wear a thick undersuit with your drysuit. You may be using a neoprene suit or a membrane one in warmer water, like that of the northern Red Sea, as many people do now during the winter.
I thought the Cool fix garment might be ideal for divers and am told it is recommended by the Danish Offshore School for Diving, at Fan. It was originally developed for the Danish army and police and is designed for use in temperatures between -5°C and +18°C.
It is made from a double layer of spun polyester and cotton knitted cloth. Air circulates within the vertical channels on the inside of the cloth, providing an insulating layer, and the fleece carries perspiration and damp away from the wearer's skin.
It looks like what it is - thermal underwear. The military-green colour scheme is anything but attractive and neither is the price!
or
